This invention relates to the manufacture of corrugated tubing from strips of ductile material such as light gauge aluminum. The machine for making such tubing disclosed herein is characterized by an adjustment which simultaneously sets the proper radius of curvature and helical angle needed to manufacture varying diameter sizes of tubing without requiring either the substitution or addition of parts.
There is a recognized need for flexible corrugated tubing especially constructed of light gauge aluminum in the heating, cooling and pressurized air fields. Such tubing is strong, resilient, and capable of being bent around a sharp radius.
Although there has been advancement in the machines utilized to manufacture corrugated tubing, the apparatus described herein represents significant improvements over existing manufacturing machines. The manufacturing apparatus disclosed in U.S. Pat. No. 4,096,720 is representative of machines currently utilized to manufacture corrugated tubing. This machine requires the substitution of parts in order to produce tubing of various diameters. When parts must be interchanged, the possibility exists for damaging the additional parts or even losing them. The instant invention overcomes these problems since no substitution or additional parts are required in order to produce different sized diameter tubing. Easier and faster changes from one size tubing diameter to another is accomplished by the current invention.
Another problem encountered in manufacturing tubing is the loading or mounting of the spool of ductile strip material from which the tubing is to be fabricated. Even if light gauge aluminum material is utilized, spools may weigh in excess of 100 pounds. It is difficult and sometimes impossible for a single man to lift such a spool in order to mount it in position for feeding the manufacturing machine. The instant invention overcomes this problem by incorporating a loading ramp and lifting mechanism which enables a single man to easily load and mount a spool of material.
Additional space is required for manufacturing tubing when the spool of strip material is mounted external to the manufacturing machine. External mounting also increases the likelihood that the thin guage strip material will be deformed or damaged before utilization. The instant invention overcomes these and related problems by enclosing the spool of material within the housing of the manufacturing machine itself.
Coupling two lengths of tubing together has presented difficulties. The instant invention produces tubing having a seam which permits adjacent strips to rotate with respect to each other. This permits the end of a length of tubing to be rotated either clockwise or counterclockwise thereby increasing or decreasing the diameter of the tubing at the end. Another length of tubing has its end rotated in the opposite direction. Thus, one length has an increased end diameter and the other has a decreased end diameter allowing insertion of the smaller diameter end into the larger. After insertion, the smaller is rotated to increase its diameter to near its original dimension and the larger is rotated to decrease its diameter to near its original dimension, thereby locking the two lengths together. This eliminates the requirement of special couplers, special machines, or complicated techniques to join lengths of tubing.
The instant invention provides a novel and improved apparatus for manufacturing corrugated tubing made of ductile strip material, such as light gauge aluminum and a method of joining corrugated tubing.